Evaluation of Physical Properties of Garlic Bulb for Processing Equipment Design
H. Shoba
Department of Agriculture Engineering, College of Horticulture, Munirabad, UHS, Bagalkot, Karnataka (583233), India.
G. Nagaraja *
Department of Agriculture Engineering, College of Horticulture, Munirabad, UHS, Bagalkot, Karnataka (583233), India.
G. Srinivas
Department of Food Process Engineering, DSLD, College of Horticulture, Devihosur, Haveri (581110), UHS, Bagalkot, Karnataka, India.
*Author to whom correspondence should be addressed.
Abstract
Physical properties of garlic bulbs are essential for the design and development of post-harvest processing, handling, grading and storage equipment. This study evaluated selected physical, gravimetric and frictional properties of fresh garlic bulbs collected from farmers in Hospet, Karnataka, India, during January to March 2023. Standard procedures were used to determine mass, principal dimensions, mean diameters, sphericity, aspect ratio, projected areas, surface area, volume estimates, density, porosity and coefficient of friction on different contact surfaces. The mean bulb mass was 11.08 g, with mean length, width and thickness of 3.82 cm, 3.20 cm and 2.73 cm, respectively. The arithmetic, geometric and equivalent mean diameters were 3.25 cm, 3.18 cm and 3.19 cm, while sphericity and aspect ratio were 0.83 and 0.84. The mean projected areas perpendicular to length, width and thickness were 9.59 cm², 8.03 cm² and 6.84 cm², with a mean surface area of 31.74 cm². The oblate spheroid, prolate spheroid and ellipsoid volumes were 20.42 cm³, 20.84 cm³ and 17.40 cm³, respectively. True density, bulk density and porosity were 334.34 kg/m³, 110.56 kg/m³ and 66.93%. The coefficient of friction was highest on plywood (0.51), followed by mild steel (0.43), and lowest on glass (0.24). The results indicate that garlic bulbs have moderately spherical geometry, appreciable bulk void space and surface-dependent frictional behaviour. Within the scope of the tested samples, these data may support the design of equipment components used in handling, conveying, grading, storage and related garlic processing operations. The measurements also provide baseline values for selecting screen openings, hopper slopes, storage capacity and suitable contact materials.
Keywords: Garlic bulb, physical properties, geometric mean diameter, bulk density, true density, porosity, coefficient of friction, projected area, surface area, processing equipment, post-harvest handling